scholarly journals Allelopathic impact of aqueous extracts of Eclipta alba L. on germination and seedling growth of Melilotus alba Medik.

2014 ◽  
Vol 9 (25) ◽  
pp. 1948-1951
Author(s):  
Raoof K. M. Abdul ◽  
M. B. Siddiqui
2021 ◽  
Vol 27 (1) ◽  
pp. 1-12
Author(s):  
Bilal Ahmad Khan ◽  
Saima Anwar ◽  
Rizwan Maqbool Maqbool ◽  
Muhammad Mohsin Amin ◽  
Muhammad Mansoor Javaid ◽  
...  

ABSTRACT Aqueous extracts of plants are used to control weeds and having no hazards to environment and are inexpensive. Present study was undertaken to investigate the effect of aqueous extracts of Sonchus oleraceus L. on the Oryza punctata L. emergence and initial seedling growth. It consists of aqueous extract of leaves, stem and fruit of S. oleraceus at varying concentrations 0.25, 0.50, 1, 2, 4 and 8 % (w/v) along with a distilled water control. The allelochemicals present in the aqueous extracts showed stimulatory, inhibitory and hormetic responses depending upon the concentration and the plant part. Results directed that maximum mean emergence time (5.26 days) and minimum germination index (1.67), germination percentage (40%), seedling fresh weight (59 g) and dry weight (8 g) of O. punctata were examined with 8% aqueous extract of S. oleraceus fruit. However, 4% aqueous extract of S. oleraceus fruit produced minimum root length (5.71). On the basis this experiment it was concluded that 8% aqueous extract of S. oleraceus fruit can be used for controlling O. punctata weed. Keywords: Aqueous extract, environment, allelochamicals, hermetic response, stimulatory ABSTRACT Aqueous extracts of plants are used to control weeds and having no hazards to environment and are inexpensive. Present study was undertaken to investigate the effect of aqueous extracts of Sonchus oleraceus L. on the Oryza punctata L. emergence and initial seedling growth. It consists of aqueous extract of leaves, stem and fruit of S. oleraceus at varying concentrations 0.25, 0.50, 1, 2, 4 and 8 % (w/v) along with a distilled water control. The allelochemicals present in the aqueous extracts showed stimulatory, inhibitory and hormetic responses depending upon the concentration and the plant part. Results directed that maximum mean emergence time (5.26 days) and minimum germination index (1.67), germination percentage (40%), seedling fresh weight (59 g) and dry weight (8 g) of O. punctata were examined with 8% aqueous extract of S. oleraceus fruit. However, 4% aqueous extract of S. oleraceus fruit produced minimum root length (5.71). On the basis this experiment it was concluded that 8% aqueous extract of S. oleraceus fruit can be used for controlling O. punctata weed. Keywords: Aqueous extract, environment, allelochamicals, hermetic response, stimulatory ABSTRACT Aqueous extracts of plants are used to control weeds and having no hazards to environment and are inexpensive. Present study was undertaken to investigate the effect of aqueous extracts of Sonchus oleraceus L. on the Oryza punctata L. emergence and initial seedling growth. It consists of aqueous extract of leaves, stem and fruit of S. oleraceus at varying concentrations 0.25, 0.50, 1, 2, 4 and 8 % (w/v) along with a distilled water control. The allelochemicals present in the aqueous extracts showed stimulatory, inhibitory and hormetic responses depending upon the concentration and the plant part. Results directed that maximum mean emergence time (5.26 days) and minimum germination index (1.67), germination percentage (40%), seedling fresh weight (59 g) and dry weight (8 g) of O. punctata were examined with 8% aqueous extract of S. oleraceus fruit. However, 4% aqueous extract of S. oleraceus fruit produced minimum root length (5.71). On the basis this experiment it was concluded that 8% aqueous extract of S. oleraceus fruit can be used for controlling O. punctata weed. Keywords: Aqueous extract, environment, allelochamicals, hermetic response, stimulatory


2015 ◽  
Vol 2 (2) ◽  
pp. 123-128
Author(s):  
Prabhakaran J ◽  
Kavitha D ◽  
Arumugam K

The present study was aimed to investigate the allelopathic influence of two weed species Cyperus rotundus L. and Cleome viscosa L. against the growth of Black gram (Vigna mungo (L.) Hepper). Aqueous extracts (5%, 10%, 25%, 50%, 75% and 100% concentrations) of whole plants of C. rotundus and C. viscosa were employed to investigate their influence on the germination and seedling growth of the black gram. The aqueous whole plants extracts ( from 5% to 100% concentrations) of C. rotundus and C. viscosa exhibited an inhibitory effects on all the parameters employed in the germination percentage, root and shoot growth, fresh and dry weight, content of chlorophyll, starch, sugar and protein contents of Black gram over control. The extracts of both the weeds caused a minimum inhibition on germination and seedling growth of Black gram at 5% concentration and the intensity of inhibition increased when increased extract concentrations. The aqueous extracts of C. rotundus and C. viscosa showed an inhibitory effect on Black gram but their effect was more severe on black gram by the extract treatments of C. rotundus than that of C. viscosa.


2014 ◽  
Vol 32 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. Mehmood ◽  
A. Tanveer ◽  
M.A. Nadeem ◽  
Z.A. Zahir

A laboratory study was conducted to investigate the allelopathic effect of aqueous extracts of plant parts of Alternanthera philoxeroides and A. sessilis and soil incorporated residues on germination and seedling growth of rice (Oryza sativa). Aqueous extracts prepared from different plant parts of Alternanthera species delayed rice germination. Alternanthera philoxeroides and A. sessilis inhibited rice germination by 9-100% and 4-49%, respectively. Germination of rice seeds was reduced with increasing concentration of aqueous leaf extracts of both weed species. Early seedling growth (root and shoot lengths) and seedling vigor index were significantly reduced by 5% aqueous leaf extract compared with distilled water treated control. Germination, root and shoot lengths, root and shoot dry weights and seedling vigor index of rice were drastically reduced by 3 and 4% in residue infested soil compared with residue free soil. The inhibitory effect of A. philoxeroides in terms of germination and seedling growth of rice was greater than that of A. sessilis. Five percent aqueous leaf extract and 4% residue infested soil of A. philoxeroides caused complete failure of rice seed germination. Alternanthera philoxeroides contained water soluble phenolics, namely 4 hydroxy-3-methoxy benzoic acid (16.19 mg L-1) and m-coumaric acid (1.48 mg L-1), whereas Alternanthera sessilis was rich in chlorogenic acid (17.85 mg L-1), gallic acid (11.03 mg L-1) and vanillic acid (9.88 mg L-1). The study indicates that the allelopathic potential of Alternanthera species may play an important role in enhancing the invasiveness of these species and may suppress rice plants in the vicinity.


Weed Science ◽  
1989 ◽  
Vol 37 (5) ◽  
pp. 665-669 ◽  
Author(s):  
Albert E. Smith

Research was conducted to determine the potential for allelopathy to occur in pastures infested with bitter sneezeweed. Aqueous extracts of bitter sneezeweed leaves reduced alfalfa and Italian ryegrass seedling growth as much as 50% at concentrations of 0.5% (w/v). Leaf extracts were more phytotoxic than either stem or root extracts and seedling growth was reduced more than seed germination. Bitter sneezeweed tissue mixed in potting soil at concentrations as low as 0.3% w/w reduced alfalfa seedling numbers by 43%, plant height by 26%, and foliage dry matter production by 54% compared to plants cultured in soil without bitter sneezeweed leaf tissue. The potential concentration of bitter sneezeweed leaf material in soil in the pasture ecosystem was determined to be 0.5% w/v in the liquid phase and 0.2% w/w in the solid phase. Alfalfa seedling growth was reduced by 70% when germinating seed were placed under a bell jar with a potted mature bitter sneezeweed plant compared to control seedlings. A potential exists for bitter sneezeweed interference with developing alfalfa and Italian ryegrass seedlings following fall interseeding into pastures infested with bitter sneezeweed.


Rodriguésia ◽  
2018 ◽  
Vol 69 (4) ◽  
pp. 2153-2161
Author(s):  
Letícia Rodrigues Vieira ◽  
Eliane Regina da Silva ◽  
Geraldo Luiz Gonçalves Soares ◽  
Claudimar Sidnei Fior ◽  
Eduardo Miranda Ethur ◽  
...  

Abstract Some exotic species threat the integrity of natural environments due to their invasive potential. They can affect other species by releasing secondary compounds in the soil. Morus nigra (Moraceae) is an invasive species of riparian forests in southern Brazil. The objective of this study was to verify if the aqueous extracts of fruit, fresh and dry leaves of M. nigra show phytotoxic effects on germination, seedling growth and membrane integrity of seedlings of Lactuca sativa. Extract concentrations of 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5 and 10% were tested. Germination rate and speed of germination were determined. Effects on initial growth were evaluated by measuring seedling root and shoot length, and membrane integrity was assessed by conductivity tests. Results showed the phytotoxicity of M. nigra aqueous extracts, causing significant inhibition on germination and seedling growth. The fruit extract was generally less phytotoxic than extracts from fresh and dry leaves. Moreover, the extracts induced changes in membrane integrity and caused morphological deformities in seedlings, such as necrotic roots and chlorotic plants. The high phytotoxicity of fruit, dry and fresh leaf extracts of M. nigra was evidenced, indicating the allelopathic potential of the species.


Botany ◽  
2020 ◽  
Vol 98 (5) ◽  
pp. 273-281
Author(s):  
Chadlia Hachani ◽  
Mohammed S. Lamhamedi ◽  
Mejda Abassi ◽  
Zoubeir Béjaoui

Biodiversity has been confronted with anthropogenic threats and several natural threats such as biological invasions. The success of these invasions involves phytotoxic products released by invasive plants that can exhibit allelopathic effects on target species. Thus, aqueous extracts from different parts of the Mediterranean yellow star-thistle [Centaurea solstitialis subsp. schouwii (DC.) Gugler], were tested for their allelopathic effects on seed germination and seedling growth of Sulla coronaria (L.). Bioassays were conducted in vitro to test the effects of the aqueous extracts of shoot, basal and root parts of C. solstitialis subsp. schouwii at two different concentrations (50 g·L−1 and 10 g·L−1). The concentrations of total polyphenols, flavonoids, and tannins of the extracts were also evaluated. Our results showed inhibitory effects on the germination and seedling growth of S. coronaria seedlings, particularly with the extract form the basal part, reaching 84%. This study confirms the linear relationships between the allelopathic effects of C. solstitialis subsp. schouwii and the polyphenol and flavonoid contents. However, further experiments are needed under field conditions to confirm the results obtained under laboratory conditions.


1970 ◽  
Vol 5 (5) ◽  
pp. 100-106 ◽  
Author(s):  
Sailaza Manandhar ◽  
Bharat B Shrestha ◽  
Hari D Lekhak

Paddy (Oryza sativa L. var. Taiching-127) fields of Kirtipur, central Nepal, were studied to evaluate the effects of weeds on crop yield during June to October 2003. Weed community was recorded in permanently marked plots (2 x 2 m2 each), and grain and straw yields were measured. The effect of aqueous extracts (2 to 10%) of leaf, stem and root of dominant weeds (Echinochloa colona, E. crusgalli, Cyperus iria and Ageratum conyzoides) on germination and seedling growth of the paddy (Taiching-127) was examined in the laboratory. Altogether 52 weed species (27 dicot and 25 monocot) belonging to 32 genera and 15 families infested the paddy. The maximum weed density was observed in September (105 pl/m2). There was significant reduction in straw and grain yield of paddy in weedy plots and negative correlation between weed species richness and straw yield. Crop weed competition reduced straw yield by 13% to 38% and grain yield by 25% to 47%. Weed growth changed pH and reduced soil nitrogen and phosphorus content. Aqueous extracts of root, stem and leaf of dominant weeds (Echinochloa colona, E. crus-galli, Cyperus iria and Ageratum conyzoides) showed a weak effect on seeds germination however most of them had inhibitory effect on root and shoot elongation of paddy seedlings. Root elongation was more sensitive to allelopathic inhibition than shoot elongation. Stem extract of these weeds showed higher inhibition on seedling growth of paddy than leaf and root extract except in Ageratum conyzoides in which root extract showed highest inhibition. Keywords: Allelopathy; Crop-weed competition; Soil nutrients; Germination; Grain yield. DOI: 10.3126/sw.v5i5.2665 Scientific World, Vol. 5, No. 5, July 2007 100-106


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